Lasers that utilize optical parametric oscillators (OPO) are well known in the art. Such lasers are desired because they can supply a large number of different wavelength beams. See U.S. Pat. No. 6,108,356 (Yin) and U.S. Pat. No. 7,079,557 (Yin). It desired that such lasers can be tuned to supply variable wavelengths from the same laser. Typically, such lasers were tuned by changing the phase matching angle of the crystal. Typically, OPO cavity mirrors were broad band to cover a range of wavelengths and the OPO crystal would be moved to change the phase matching angle. OPO lasers have been disclosed having pump beams of variable wavelength which can change the wavelength generated by the OPO crystal. See U.S. Pat. Nos. 6,710,914 (Arbore) and 6,304,585 (Sanders). There is still a need for simple tunable OPO lasers.